Enter text for each circle and the overlap, and optionally change the colours of the circles.
Alt text will be suggested here once an image has been generated.
Alt text is used to describe images for people who can't otherwise view them.
For example, someone who is partially sighted might use software called a screen reader, where the computer reads out what's on the screen. Alt text is used by that software, since computers aren't able to accurately describe an image without help.
If you're sharing images on social media, please consider adding alt text so that they're accessible to everyone. Some of my generators offer suggested alt text that you can copy and paste to make it easier.